Question: What is the collection of astronomical objects with the smallest wavelength?
Paraphrase: What collection of actronomical objects has the smallest wavelength?
SPARQL (Wikidata): select ?ent where { ?ent wdt:P31 wd:Q605175 . ?ent wdt:P2808 ?obj . ?ent wdt:P31 wd:Q605175. } ORDER BY ASC(?obj)LIMIT 5 
Answer: 2MASS, 2MASS, 2MASS, Fourth Cambridge Survey, Third Cambridge Catalogue of Radio Sources